1) Field of the Invention
The present invention relates generally to cotton harvesters, and more specifically to a cotton harvester row unit which is able to operate at higher speeds than most conventional row units for increased harvester productivity.
2) Related Art
In the past, cotton harvesters of the spindle type such as the John Deere model 9910 Cotton Picker included row units with front and rear picker drums located to pick cotton from the opposite sides of the row. The forward drum typically included 16 upright bars of spindles and the rear drum had 12 bars of spindles. This configuration of drums required a relatively wide housing which limited the harvester to harvesting only two widely spaced (38 or 40 inches) rows. To accommodate simultaneous harvesting of four rows of cotton, units were designed with front and rear 12-bar drums picking from opposite sides of the row, but these units also required the wide row spacings.
More recently, narrow row cotton harvesters have been available commercially which are capable of harvesting four or more rows of cotton spaced as narrowly as 30 inches. One type of narrow row harvester, exemplified by the Case-IH model 2055 Cotton Picker, has nested units with two 12-bar drums on opposite sides of the row. A second type of narrow row harvester, exemplified by the John Deere model 9960 Cotton Picker, utilizes two 12-bar drums located on the same side of the row. To improve picking efficiency and doffing in tough high yield conditions, the cam which controls the movement of the bars is designed to maximize the time that the spindles are in the row and under the doffers. Such time maximization, however, requires high angular acceleration of the bar about its axis in the transition area between the row-receiving area and the doffers and significantly increases the cam roller and picker bar loads so that the speed at which the 12-bar drums can operate is limited. The maximum drum speed determines the maximum ground speed of the harvester since ideally the forward ground speed and the rearward spindle speed in the row are identical; therefore, the harvesting speed on present pickers is limited by the drum loading. Increasing drum size to reduce loading has heretofore been avoided, especially in narrow row units, in part because of space and front end weight constraints.